Metal Rubber Research Articles

Research on Electrical Characteristics of Metal Rubber

Metal rubber is a new type of elastic damping material. It’s often used in all kinds of instruments and equipment to vibration isolation and buffer. The internal of metal rubber is mesh structure in space formed with wires. The contact points of the crossed wires aren’t solid collusion. Although the compressive strength of metal rubber is very good, but the structure of metal rubber would become loosly and destroyed under tensile load. Literature [1] put forward that the pulse discharge sintered to metal rubber can make the contact point transform to solid collusion. The method is based on the theory of resistance welding to the contact points between sintering metal wires in metal rubber. The research and analysis to the electricity characteristics of the metal rubber has important significance to optimize parameters of electrical pulse discharge experiment and improve the quality of sinter.

High frequency noise suppression of the automobile exhaust system

The paper presents the decision for the question of the excessive catalytic collector high frequency noise in the automobile engine exhaust system. The high level noise has been observed under the idle state engine condition. In order to understand the causes of the high catalytic collector noise emission the research of its vibroacoustic internals has been performed. An experimental stand for the acoustic and vibration response on broadband dynamic excitation tests has been created. The power of the acoustic noise, emitted by the catalytic collector and vibration distribution of its surface have been defined. It was found that the catalytic collector surface has the low acoustic impedance in the high frequency range. The surface vibration damper design has been developed. A special material, so called metal rubber, has been used to damp the vibration. The main advantage of this material is the temperature tolerance, quite useful for the engine exhaust system unit. The use of the damper has allowed to reduce the structure-born noise of the catalytic collector.
 
 Key words: catalytic collector; structure-born noise; automobile; acoustic power; acoustic impedance; metal rubber

Simulation and Springback Verification for Rubber Bladder Forming with a Definite Aircraft Part

Springback is a main problem in sheet metal rubber bladder forming that influences the geometric accuracy of a part. In this paper, springback distribution of a certain aircraft part is analyzed by finite element simulation and verified the accuracy of relevant equations. The aircraft part is divided into six convex flanging areas for analysis, several technological parameters are taken into consider, and the results of simulation and equation calculation are well agreed, the influence of a joggle is also discussed.

The Development of Database of Rubber Bladder Forming Process Parameters Based on Visual Basic

Forming process parameters are used for providing reference to forming process and die design, which are achieved from uniaxial tension and simulation tests. The forming characteristics in the as-quenching conditions are different from the annealing and T3 status. Database is involved in any kind of hydraulic stretch forming materials parameters used. Its application scope is broad. The graphics data and attribute data are managed using SQL server relation-database technology, management information system is developed by using Visual Basic. The database is convenient to query, retrieve for relevant personnel .Then it provides reliable basis for sheet metal rubber bladder forming more accurately.

Quality assurance of diaphragm walls by sonar measurements – model study

Diaphragm walls are used to provide a stable and water-tight confinement for the construction of tunnels, underground railway stations, deep basements and other structures requiring deep excavations. These walls consist of individual panels, cast piece-wise in the ground, separated by water-tight joints. There are several methods to improve the water tightness of these joints, including rubber bands, metal sheets or precast concrete elements. In most cases, diaphragm walls perform very well. Quality problems, which occur in a few occasions, may be due to uncontrolled concrete flow between the joints, unexpected geological conditions or poor workmanship. Different methods of quality assurance are applied on construction sites. Sonar instruments can be used in a bentonite-filled trench to evaluate the shape of the excavation. An improved prototype instrument has been developed, including digital data-processing features, which allow the detection of even small anomalies at the stop-end surface before concreting the adjacent panel. The sonar sensor can be used in depths up to 200 m. Model experiments show that a centimetre resolution can be achieved. Set-up, model experiments and their results are shown. The prototype might be the basis of an easy-to-use commercial device.

Energy dissipation of a ring-like metal rubber isolator

Metal rubber (MR) is a kind of homogeneous poroelastic damping material made of metal wire. In this paper, by analyzing the forces on the MR isolator and the MR element, the hysteresis loops of the force and deformation are studied and verified by experiments. The results show that the force and displacement hysteresis loop of the MR isolator is described by the force and deformation hysteresis loops of the MR elements. In addition, the relationship between the energy dissipation coefficient of the MR element and that of the MR isolator is derived. The energy dissipation coefficient is programmed and calculated by MATLAB using experimental data, and the results are compared with the theoretical value. It is the basis for the design and applied research of the MR isolator in a future study.

Parameter Identification of a New Metal Rubber Damper System

The parameter identification of a new hysteretic nonlinear metal rubber damper system is studied in this paper. Firstly, the advantage of the new metal rubber damper which composed by two components is proved by the static and dynamic test comparing to the damper included only one metal rubber. Secondly, the constitutive of bilinear hysteresis model and parameter identification equation are obtained. Then the parameter of the new damper system is identified by generalized least squares estimation. In the last, the simulation result is compared with the real values, it shows that the method is simple, effective, high precision, and it is also reliable and applicable to the corresponding engineering.

Research on Electromagnetic Shielding Efficiency of Metal Rubber Material

Beginning from the manufacture process of metal rubber material, the structure and electromagnetic shielding mechanic were studied. Based on the flange coaxial test, the shielding efficiency of metal rubber samples was measured and the mathematic model of electromagnetic shielding efficiency was deduced. Using Schelkunoff formula the number and fitting curve of shielding efficiency were got. It can be concluded as a new kind of functional material, the metal rubber material would be widely used in the field of electromagnetic shielding and packing.

Spiral Roll Forming Machine Design for Metal Rubber

Metal Rubber made by the specific process has excellent mechanical properties. Spiral coil winding is one of the keys in the process of forming Metal Rubber. This paper introduces the forming principle of the metal rubber spiral coil and the control of resilience amount in the forming process. A Spiral roll forming machine is designed for Metal rubber and it can be controlled automatically.

Study on Dedicated Test Bed for the Sealing Performance of Metal Rubber Seal

Dedicated TestBed (DTB) for detecting the sealing performance of Metal Rubber (MR) was designed and manufactured based on Siemens S7-200 PLC. The experiments, such as high temperature and large temperature difference experiment, could be conducted with real-time monitoring by DTB. The general design including mechanical and control part of DTB is introduced in detail.

Dynamic mechanical behavior of nickel-based superalloy metal rubber

The work describes the manufacturing and dynamic characterization of nickel wire-based metal rubber (MR) solids. The storage modulus and the loss factor of the nickel MR samples are measured over a frequency range between 0.1Hz and 200Hz, and at different levels of dynamic force and strain using a dynamic mechanical analyzer (DMA) technique. A sensitivity analysis about the effect of different static and dynamic testing parameters is initially carried out to identify suitable testing protocols for this metal porous material. DMA testing is then carried out over three different batches of samples (5 specimens each) with variable relative densities to identify the correlation between storage modulus and loss factors with frequency and dynamic force and strain levels. The results are discussed using a mechanical theoretical model relating the mechanical properties of MR solids to the contact states of the wire composing the microstructure. A comparison with analogous results obtained from cyclic tests at 1Hz from a conventional tensile machine is also performed. The results from this benchmark highlight the necessity to use dynamic-based testing protocols to efficiently implement nickel-based metal rubber for vibration damping and energy absorption designs and applications.

Experimental Investigation on Damping Characteristic of Metal Rubber Material at Simulated Marine Environment

To meet the need of damping material at the marine corrosive environment, the clamped-edge disk type of metal rubber specimen is designed and its corrosion-load alternate experiment is performed, the anti-corrosive and damping characteristic of the material at the marine corrosive environment is researched. The experimental results show that the corrosive rate of 304 stainless steel metal rubber specimen at cycle-immersion corrosion-load alternate environment is the highest and its decay rate of dynamic average rigidity is also the highest, and followed by full-immersion, cycle-salt-spray and full-salt-spray environment. The damping characteristic of metal rubber specimen is relatively stable at the corrosion-load alternate experiment; the metal rubber material has anti-corrosion ability at marine environment.

Experimental Study on Mechanical Characteristics of Knitted-Dapped Metal Rubber

Knitted-dapped metal rubber was developed to solve problems of metal rubber with low stiffness and test samples with different sizes were manufactured. Static tests and dynamic tests were carried out to study influences of density and thickness on the static stiffness and influences of frequency, amplitude and preload on dynamic characteristics. Results show that static stiffness rises when density or thickness increases. Frequency has little influence on dynamic characteristics. Knitted-dapped metal rubber will have smaller stiffness and better characteristics of damping, if amplitude increases; if preload increases, energy consumed in the vibration will be more.

Theoretical Model Research of Metal Rubber Material

Metal rubber is a kind of pure metal structure of the porous material. The paper, starting from the internal structure of metal rubber, based on the theory of porous, based on dry friction nonlinear theory, establishing the unit model of porous metal rubber material, for the development of product design and application of the metal rubber material to provide a theoretical basis.

Experimental Study on Fatigue of Metal Rubber Vibration Isolator under Pulsating Cyclic Stress

Metal Rubber(MR) vibration isolator is a new type of isolator developed to overcome the fatal aging phenomenon of current rubber isolator. It has broad practical application in the military, such as aerospace. In this paper, the fatigue life experiment is conducted to MR vibration isolator, and resonant frequency and resonant accelerate transmissibility are chose as degradation parameters. It’s found that MR vibration isolator possesses jump phenomenon; resonant frequency and resonant transmissibility increase quickly to the maximum, then attenuate slowly with the increasing number of vibration. This provides fundamental basis for the design and application research of MR vibration isolators.

A nonlinear auxetic structural vibration damper with metal rubber particles

The work describes the mechanical performance of a metal rubber particles (MRP) damper design based on an auxetic (negative Poisson’s ratio) cellular configuration. The auxetic damper configuration is constituted by an anti-tetrachiral honeycomb, where the cylinders are filled with the MRP material. The MRP samples have been subjected to quasi-static loading to measure the stiffness and loss factor from the static hysteresis curve. A parametric experimental analysis has been carried out to investigate the effect of relative density and filling percentage on the static performance of the MRP, and to identify design guidelines for best use of MRP devices. An experimental assessment of the integrated auxetic-MRP damper concept has been provided through static and dynamic force response techniques.

Theoretical and experimental steady-state rotordynamics of an adaptive Air Film Damper with Metal Rubber

An Air Film Damper (AFD) made with a highly damping material called Metal Rubber (MR) as the outer ring is a novel damping structure that aims to reduce the remarkable vibrations produced by a flexible rotor system. The mechanism of an AFD is firstly put forward and the mechanical model describing the fluid structure interaction is constructed. Taking into consideration the complex whirl of the rotor and the precession of the floating ring, the Reynolds equation of AFDs is derived and the air film pressure is obtained. Based on these calculations, the selection of MR stiffness is introduced and the adaptive properties of AFD are analyzed. Then the effects of AFD on the rotordynamics are studied based on the characterization of the parameters of a rotor system in the steady state. The mechanism and the effects of AFD on a rotor system are verified through rotating experimental tests. The theoretical and experimental results both show that AFD can adjust the air film clearance adaptively according to the vibration of the rotor; this can not only decrease the friction between the journal and the floating ring, but can also provide additional stiffness and damping to the rotor system, thus yielding additional vibration control.

Compression mechanics of nickel-based superalloy metal rubber

The work describes the manufacturing and testing of metal rubber (MR) samples produced from nickel-based superalloys, and subjected to compression loading in quasi-static regime, three batches of MRs with different relative densities have been fabricated, and their mechanical properties (tangent modulus, loss factor and Poisson's ratio) have been investigated at different maximum strains, and under cyclic loading. The experiments show the significant effect of the MRs' relative density over the global mechanical compression properties, with the tangent modulus increasing and the loss factor from the hysteretic cycles decreasing in samples with higher density. At low strain level, metal rubber appears to behave like a zero Poisson's ratio material. The results show the effectiveness in controlling the mechanical properties of nickel-based metal rubber by careful adjusting of the relative density during manufacturing.

System identification methods for metal rubber devices

Metal rubber (MR) devices, a new wire mesh material, have been extensively used in recent years due to several unique properties especially in adverse environments. Although many practical studies have been completed, the related theoretical research on metal rubber is still in its infancy. In this paper, a semi-constitutive dynamic model that involves nonlinear elastic stiffness, nonlinear viscous damping and bilinear hysteresis Coulomb damping is adopted to model MR devices. The model is first approximated by representing the bilinear hysteresis damping as Chebyshev polynomials of the first kind and then generalised by taking into account the effects of noises. A very efficient systematic procedure based on the orthogonal least squares (OLS) algorithm, the adjustable prediction error sum of squares (APRESS) criterion and the nonlinear model validity tests is proposed for model structure detection and parameter estimation of MR devices for the first time. The OLS algorithm provides a powerful tool to effectively select the significant model terms step by step, one at a time, by orthogonalising the associated terms and maximising the error reduction ratio, in a forward stepwise manner. The APRESS statistic regularises the OLS algorithm to facilitate the determination of the optimal number of model terms that should be included into the model. And whether the final identified dynamic model is adequate and acceptable is determined by the model validity tests. Because of the orthogonal property of the OLS algorithm, the selection of the dynamic model terms and noise model terms are totally decoupled and the approach also leads to a parsimonious model. Numerical ill-conditioning problems which can arise in the conventional least squares algorithm can be avoided as well. The methods of choosing the sampling interval for nonlinear systems are also incorporated into the approach. Finally by utilising the response of a cylindrical MR specimen, it is shown how the model structure can be detected in a practical application.

Metallic Counterpart of Rubber: a Material for Vibration and Shock Protection

Data on the development, research and engineering applications of a metallic porous material with unique damping properties and superhigh elasticity, which is known as a “metallic counterpart of rubber” or briefly as “metallic rubber,” are presented. The process of production of such a material is considered including cold pressing of a metallic preform from coiled wire and formation of a porous structure. Amathematical model of cyclic deformation of articles from metallic rubber is developed and used to compute the parameters of various dampers and vibration isolators.